Support middlewares out-of-the-box

[Weakky]

Description

There are two types of middleware that should be easily definable with Yoga:

• "HTTP" middleware: most probably express middlewares
• GraphQL middleware: a function to be run before (or after) a resolver is executed
  • middlewares should be definable at every level (globally, type-level, field-level)

Current state:

• HTTP middleware: Only possible by ejecting
• GraphQL middleware: Only possible by ejecting (eg: using graphql-middleware)

Ideally, both HTTP middlewares and GraphQL middlewares should be definable without having to eject.

Unfortunately, because Yoga doesn't require a server to be defined by default, users have no way to access the underlying components.

• Fortunately, for GraphQL middlewares, this can be done on the schema layer and thus should be handled by nexus (Proposal here: Support middleware graphql-nexus/nexus#64)
• For HTTP middlewares however, we need to find an elegant way to expose the underlying express instance for people to compose with it

Motivation

Obvious use-cases:

• Authorization (How to handle authentication with yoga? #34)
• Authentication (How to handle authorization with yoga? #35)
• Logging
• Input validation
• ...

Some ideas

Accessing the underlying express instance

Option 1

Have an express folder, in which all files gets the underlying express instance injected

export default ({ app }) => {
  // app.use(passport.initialize())
  // app.post('/login', ...)
}

Option 2

Do we really need several files in a folder? What about a single express.ts file ?

import { logging, otherMiddleware } from './express-middleware'

export default ({ app }) => {
  // app.use(logging)  
  // app.post('/login', otherMiddleware, handler)
  // app.post('/logout', otherMiddleware, handler)
}

Option 3

Any better idea?

---

Because HTTP middlewares and GraphQL middlewares are two different concepts, it feels hard to come up with an API that elegantly conciles the two.

We'd love to hear feedback/different API design for express middlewares as well as nexus middlewares 🙌

Thanks!

[Weakky]

Option 2 was released under [email protected] for accessing express middlewares

[DevanB]

Thanks for this @Weakky! I'm very curious to see graphql middlewares support without ejecting soon. Until then, I'll simply eject (since it's a reversible process 😄 )

[ivan-kleshnin]

Would be great if someone clarified how Prisma 2, Yoga 2 and Prisma Nexus are or will be related 😓
I'm kinda lost here. There are so many moving parts changing as I'm typing it.

[DevanB]

@ivan-kleshnin I think this question is better asked in the Prisma forum for all to see there, not as a comment on a middlewares discussion issue.